Air heater and circulator



June 22, 1948. F. R. HIGLEY EI'AL AIR HEATER AND CIRCULATOR Original Filed Aug. 12, 194].

:10 0mm p 15 INVENTORfi f if z 8/6 r05 ATTORNEY5 Patented June 22, 1948 AIR HEATER AND CIRCULATOR. Frank R. Higley, Cleveland Heights, and Eric H.

' Ryden,

Elyria, Ohi Heater Company, a corporation of Ohio assignors to Bryant Substituted for abandoned application Serial No. 406,500, August 12, 1941. This application February 8, 1946, Serial No. 646,414

2 Claims. 1

This invention relates to improvements in air heaters and circulators, in other words apparatus for heating and circulating air. With respect to certain of its features the present invention resembles to some extent that of our co-pending application Serial No. 393,302, filed May 13, 1941, and now Patent No. 2,361,545, dated October 31, 1944. This application replaces application Serial No. 406,500, filed August 12, 1941, by the applicants herein and since held abandoned.

One of the objects of the present invention is the provision of a forced air heater embodying a blower having a horizontal rotor and a scroll, a portion of which consists of a hollow casting constituting a conductor for hot gases, this casting serving for combustion chamber and that portion of the curved scroll wall along which flows the relatively high velocity air, that is to say the portion which is nearest the rotor.

Another object of the inventon is to permit the use of a relatively short casting for the purposes above indicated, thereby reducing the difliculties embodiment of the invention which, for the purposes of the present application, we have illustrated in the accompanying drawing in which Fig. 1 is a side elevational view somewhat diagrammatic in character and partly in vertical section, of a furnace embodying the invention.

Fig. 2 is a horizontal sectional view of the same, taken substantially on the line 2-4 of Fig. 1.

Fig. 3 is a detail sectional view on a larger scale taken substantially on the line 3-3 of Fig. 1, and

Figs. 4 and 5 are fragmental plan views, also on a larger scale, of the two ends of the flue connection shown in Fig. 3.

In the drawing, a rectangular sheet metal casing constituting the outer wall of the furnace is shown at I0. It is provided at the top with an opening H for the admission of air to be heated, and an air filter shown conventionally at 12 is provided inside the casing in order to remove any dust carried by the entering air.

The base i3 of the casing which, of course,

' may be suitably re-enforced, supports a hollow metal casting M which is elongated in a generally upright direction. As indicated in Fig. 2 this casting may be of substantially square section at 2 the base. Its tnansverse dimension remains substantially the same throughout its height, but

its dimensions from front to rear decrease materially above the base portion, as will be evident from an inspection of Fig. 1.

A burner of any suitable character is mounted in the base portion of the casting, a gas burner 15 being illustrated herein with the controls 16 therefor in a separate chamber ll formed by one wall of the casting l4 and sheet metal partition members in the lower portion of the space enclosed by the casing.

A part [8 of the rear or inner wall of the casting is curved spinally. Its front wall slopes toward the rear, as shown in Fig. 1, with the result that the passage through the hollow casting is constricted considerably near the top. An opening in this front wall covered by a removable cap 19 serves to admit a brush or other tool when the interior of the casting requires cleaning. If desired, the front and rear walls may be ribbed to provide increased surface in the manner indicated in our co-pending application above re ferred to.

The wall I8 constitutes part of the spiral wall of the scroll of a centrifugal blower, the rotor shaft of which is illustrated at 20. The periphery of the wheel or rotor is indicated by the dotted line 2|. one of which is shown at 22, overlap slightly the casting l4 and are suitably secured thereto. The scroll also has a sheet metal curved wall portion 23 which constitutes a continuation of the wall iii of the casting. Bearings for shaft 20 are suitably supported preferably from the side walls 22 of the scroll, and the side walls have openings at opposite ends of the rotor for admission of air thereto. A pulley 24 on the shaft is driven by a belt 25 which runs over the pulley of an electric motor 26 that may be supported above the base l3 of the casing on a bracket 21. 28 is 'an air delivery extension of the blower scroll protruding through the top of the casing I0 to which the warm air ducts of a heating system may be connected. Y

A partition 29 extends entirely across the casing in front of the extension 28 down to the side plates 22 of the scroll, and from that point partitions 30 bridge the spaces between the scroll and the two side walls of the casing down to a level below that of the rotor shaft. Consequently air entering the furnace must flow'downwardly over the outer or front wall of the casting l4 past the bottom edges of partitions 30 before it can enter the blower.

The two side walls of the scroll,

'At' therear of the casing a flue pipe 3| joins a flue connection 32, the latter extending horizontally across the delivery extension 28 of the blower and being attached 'at its forward end to a minimum, and the fins or ribs are arranged in the direction of air flow for a similar purpose. Hot products of combustion from the burner I5 flow upwardlyv through the hollow casting and thence through the flue connection 32 out through the flue 'pipe 3|.

A water pan or trough 33, in which water'is preferably maintained at a constant level automatically by suitable known means, not shown. serves to humidify the air before it enters the blower.

In blowers of the type illustrated the velocity of the air flowing through the spiral path is greatest at the most constricted part of that path, that is where the curved wall of the scroll is closest to the rotor. If a portion only of the encircling wall of this path is to be heated it is important that such portion be that. where the air travel is most rapid, because then the rate of heat exchange will'be high. For that reason we have placed the curved surface ill of our casting adjacent the cut of! end 34 of the scroll spiral; that is, we have arranged one end of it near the point where the curved scroll wall is nearest the rotor and have continued it from that point due to convection only, which is likewise the case with respect to the flue connection 32. The rear wall of the casting ll is also heated by convection. It will be seen, therefore, that the air to be treated strikes the front wall of the casting first, where it is preliminarily heated. Next it passes into the blower and is moved thereby rapidly over the wall l8, first in the convection-heated portion and then in the portion heated by radiant heat, after which it travels over the flue connection 32 heated by convection.

,The construction is exceedingly compact, and covers a wide range of heat requirements at an efliciency which remains almost constant over that range.

It would be possible to apply heat to the scroll wall through a somewhat greater angle than that illustrated, but that would'mean a larger hollow casting, and castings of this kind are difflcult and costly to produce. In the present instance by utilizing the flue connection 32 we have not merely compensated for heating a limited length of the scroll but have, in fact, increased the total a heating area and the total heating effect over what could have been attained by the use of a longer "casting l4. Furthermore, whether the flue connection '32 be a casting or a sheet metal member, the cost of the two parts It and 32 will be appreciably less than the cost of a single casting taking in another considerable portion of the scroll wall.

We claim:-

1. In an air heater and circulator, a centrifugal blower comprising a rotor and a scroll, the rotor having a horizontal axis, a delivery extension for the blower, a combustion chamber and a conductor for all gases therefrom constituting that side of the scroll which is radially innermost, said conductor extending into the angle between the scroll and the extension, means for directing entering air against said conductor adjacent said angle, a flue connection positioned across the extension and connected with the outlet end of said gas conductor, the passage for hot gases varying in shape from the gas conductor where the trans- ,verse dimension is the greater, to the said flue connection, where the dimension in the direction of air flow is the greater.

2. In an air heater and circulator, a centrifugal blower comprising a rotor and a scroll, the rotor having a horizontal axis, a delivery extension for the blower, a combustion chamber and a hot gas conductor constituting that side of the scroll which is radially innermost, said conductor extending around the innermost part of the scroll into the angle between the scroll and the said extension, a flue connection positioned across the extension and connected with the upper end of said gas conductor, and a clean-out door in the outer wall of said gas conductor adjacent said angle, whereby a cleaning brush may be inserted through the said door downwardly into the gas conductor or through the said conductor into said flue connection.

' FRANK R. HIGLEY.

ERIC H. RYDEN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

